Filters for solar

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denababy
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Filters for solar

Post by denababy »

Hi it’s been a while since I last posted here. Today’s question is, can I use a uhc filter at the front of my diagonal? The scope I will be using is an Explore Scientific ed80apo and a chromosphere Quark. I don’t have a front of the scope filter as I am informed that below 100 mm I would be ok with a filter before the diagonal and the Quark, but I could be wrong. Anyone advise please.


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DeepSolar64
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Re: Filters for solar

Post by DeepSolar64 »

80mm and below are ok with a Quark. Yes. Anything bigger would require a front mounted energy rejection filter ( ERF ).

I would mount any other filter behind the diagonal just as I would with the use of a solar wedge.


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denababy
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Re: Filters for solar

Post by denababy »

Hi it’s been a while but I have been looking to put a derf on the front of my Explore Scientific ed80apo so I have measured the front of the scope and it’s 40cm but which filter do I need. Anyone help and advise please.


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Re: Filters for solar

Post by RodAstro »

Hi
You shouldn't need a ERF with a 80mm and quark.
A UV/IR cut filter will reflect back out most of the heat and harmful UV, the Quark filter will also do that but the UV/IR will take some of the strain off the Quark filter and it may last longer. UV/IRs are cheap enough so no reason not to use one.
I would get the Quark and see how you go as it is safe to use.
All a ERF will do is stop some of the heat warming the inside of the scope causing tube currents, mainly the matt black light baffles, If you feel that is happening then try a ERF.
I use a SW ST102 with my Quark and have a full aperture ERF and see no difference so it sits in the cupboard never to be used as it is safe there.
I also use my Quark most of the time on my 150mm refractor but it is a very different scope having no light baffles I don't see any tube currents, as the light never touches the inside of the tube.
The only thing I would look at is, does the focuser have any plastic parts that the light may focus upon as you may need a ERF to stop them melting but if it is all metal no problem.
If you get a ERF then the 75 mm one should be enough, it will stop down the outer part of the objective, the worst bit optically but it will also bring you to a final f ratio of near f30 where the Quark really works well.
Actually stopping down the scope at the front will stop a lot of the light beam hitting the internal baffles helping with tube currents, getting to something near f30-f40 and the Quark is at its best, so maybe try stopping down a little first.

I hope my experience is useful, the only other thing I can say is you wont make anything worse by using a ERF, apart from your wallet.
You will also need a cell machining to attach the ERF, another cost.

Cheers Rod


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